Table - Private Streets Private Roads
Class A
Class B
Eligibility/Applicability
Ultimate development/service potential of 5 or more lots
Ultimate development/service potential of 4 or fewer lots
Minimum Easement Width (feet) Curb and Gutter Section
40
40
Shoulder Section
45
45
Utility Easements
In easement
In easement
Minimum Road Width (ft) Curb and Gutter Section
26
18
Shoulder Section
18
16
Road Construction Base Course
8" minimum thickness of ABC
Unpaved Gravel - 8” minimum thickness of ABC or Paved - 2.5” minimum thickness of S9.5B asphalt concrete over 6” ABC
Pavement Surface
2.5” minimum thickness of S9.5B asphalt concrete
Minimum Shoulder Width (ft)
4-6
4
Maximum Cut & Fill Slopes
1.1:1; must be seeded or otherwise stabilized
1.5:1; must be seeded or otherwise stabilized
Design Speed
20 mph
15 mph
Minimum Sight Distance on Vertical Curves
115
80
Maximum Rate of Vertical Curvature (K) (for minimum sight distance) Crest 10 10 Sag 17 10 Min. Centerline Radius (feet) 90 90 Maximum Grade 18%
15% for gravel or stone; 18% if paved
Drainage Design
10-25-year
25-year
Culvert Diameter (interior)
25Y Cross=18"; Drive=15"
15 inches
Cul-de-sacs Turnaround Types
Bulb-end design, T-type or Loop Road
Bulb-end design, T-type or Loop Road
Minimum ROW Radius (feet) Curb & Gutter Section
45
45
Shoulder Section
50
50
Minimum Pavement Radius Curb & Gutter Section
37
35
Shoulder Section
35
35
Maximum Length (feet)
2,500
2,500
Intersections
Minimum Spacing (feet)
135
135
Made with FlippingBook interactive PDF creator